Bridge Designs: Fixed-fixed Vs Cantilever

Question 1

What is the optimum and acceptable crown root ratios?

Answer 1

Optimum = 2:3
Acceptable = 1:1

Question 2

When would a crown-root ratio of less than 1:1 be acceptable?

Answer 2

If the opposing occlusion is composed of artificial teeth; denture or bridge
If the opposing teeth are periodontally compromised and mobile

Question 3

Ideal root configuration for a FPD

Answer 3

Roots broader labiolingually than mesiodistally over roots which are round in cross section
Multirooted teeth with widely separated roots over converged or fused roots
Roots with apical curvature over straight and near perfect taper

Question 4

When are double abutments used for FPDs

Answer 4

Unfavourable crown-root ratios of abutments

Long spans

Question 5

Criterion for double abutments in FPDs

Answer 5

A secondary abutment must have at least as much root surface area and as favourable a crown-root ratio as the primary abutment.
Must be sufficient crown length and space between adjacent abutments to prevent impingement on the gingiva under the connector

Question 6

What is a complication?

Answer 6

A secondary disease or condition developing in the course of a primary disease or condition

Question 7

Goodacre, 2003. Most common single crown complications?

Answer 7

Need for endodontic treatment
Porcelain fracture
Loss of retention
Periodontal disease 
Caries

Question 8

Goodacre, 2003. Most common fixed partial denture complications?

Answer 8

Caries
Need for endodontic treatment 
Loss of retention 
Aesthetics 
Periodontal disease 
Tooth fracture 
Prostheses fracture 
Porcelain veneer fracture

Question 9

Goodacre, 2003. Most common all ceramic crown complications?

Answer 9

Fracture 
Loss of retention
Pulpal health 
Caries 
Periodontal disease

Question 10

Goodacre, 2003. Most common RBB complications?

Answer 10

De-bonding 
Tooth discolouration
Caries 
Porcelain fracture 
Periodontal disease

Question 11

Goodacre, 2003. Most common post and core complications?

Answer 11

Post loosening
Root fracture
Caries
Periodontal disease

Question 12

Pjetursson and Lang, 2008. 
Estimated 5 year survival of: 
1. Conventional tooth-supported FDP
2. Cantilever FPD
3. Solely implant-supported FDP
4. Combined tooth-implant-supported FDP
5. Implant supported single crown
6. RBB

Answer 12

Pjetursson and Lang, 2008.
Estimated 5 year survival of:
1. Conventional tooth-supported FDP = 93.8%
2. Cantilever FPD = 91.4%
3. Solely implant-supported FDP = 95.2%
4. Combined tooth-implant-supported FDP = 95.5%
5. Implant supported single crown = 94.5%
6. RBB = 87.7%

Question 13

Pjetursson and Lang, 2008. 
Estimated 10 year survival of: 
1. Conventional tooth-supported FDP
2. Cantilever FPD
3. Solely implant-supported FDP
4. Combined tooth-implant-supported FDP
5. Implant supported single crown
6. RBB

Answer 13

Pjetursson and Lang, 2008.
Estimated 10 year survival of:
1. Conventional tooth-supported FDP = 89.2%
2. Cantilever FPD = 80.3%
3. Solely implant-supported FDP 86.7%
4. Combined tooth-implant-supported FDP = 77.8%
5. Implant supported single crown = 89.4%
6. RBB = 65%